The present invention relates to tertiary oil recovery processes, compositions for use therein, and an oil recovery system treated therewith.
Carbon dioxide has been used in secondary oil recovery processes. These secondary recovery processes entail injecting water containing carbon dioxide into an oil-bearing formation in order to increase the recoverable amount of oil from the formation. Because of insufficient transfer of carbon dioxide from the water to the oil, attempts have been made to increase the solubility, and therefore the concentration, of carbon dioxide in the water.
In addition, carbon dioxide has been co-injected with steam in tertiary oil recovery processes. Although the amount of carbon dioxide available for transfer to the oil is high, these tertiary process are unsatisfactory because well tubing and other oil recovery equipment are corroded by contact with the steam-carbon dioxide mixture.